Preserving food at home is great fun and very rewarding. Following a few basic steps should ensure food safety and quality.
Here we are talking pickles, Jams and chutneys using high levels of salt, sugar, acid, or alcohol all of which inhibit bacterial growth. Hence the use of lots of sugar and vinegar in chutneys and generally 50% sugar in jam.
Where we are dealing in products which have low levels of the above the food needs to be processed at much higher temperatures to kill off the bugs, at least 121˚c for a minimum of 3 minutes. And at home this generally means the use of pressure cooking to produce the temperatures needed.
Improper cleaning or processing can lead to Botulism. A particularly nasty food poisoning the toxins of which attack the nervous system leading to hospitalisation. Its main cause is bad packaging- damaged tins or blown plastic on pre-packed foods or pouches. Botulism is found in soil and if traces of it find there way into the food and we remove the air it can thrive and form toxins which are extremely bad for us. My advice is to stay away from high temperature preserving at home. I not against a pressure cooker but it often spoils delicate foods and flavours.
Improper cleaning or processing can lead to Botulism. A particularly nasty food poisoning the toxins of which attack the nervous system leading to hospitalisation. Its main cause is bad packaging- damaged tins or blown plastic on pre-packed foods or pouches. Botulism is found in soil and if traces of it find their way into the food and we remove the air it can thrive and form toxins which are extremely bad for us. My advice is to stay away from high temperature preserving at home. I not against a pressure cooker but it often spoils delicate foods and flavours.
If any of these are evident in your preserves, destroy them:-
Gas escaping when you open the lid.
Signs of gas bubbles in the product.
Fungus or mold on the product or lid
Discoloration of the product.
Sterilising preserving jars.
We all like to save money, and recycling jars for jams and chutneys is a great for the environment, if we understand the fundamentals.
If you are using purpose made jars it should be possible to buy new lids. This is the best option to ensure your preserves last through to the next year. Rather than using old, damaged lids from recycled jars its often better to cover the jar with cellophane after the waxed paper disc. Bear in mind the preserve won’t keep as long. With Kilner type jars always use a new rubber seal kept in near boiling water for at least 3 minutes.
There are four common methods of preparing the jars for use and killing off any nasty bugs or yeasts that will ruin in all our hard work. Sterilising the jars is a very important process, it doesn’t take that long and should never be skipped. Remember the golden rule – When in doubt throw it out!
Always sterilise more jars that you think you need. It’s a pain to find you are one or two short when filling and sealing the jars. The jars and filling must both be hot when filling and sealing the jars. As the filling cools, it will contract and form a natural vacuum to help preserve the contents.
As I said earlier there are three common methods for sterilising preserving jars
1. Use the dishwasher – rinse the jars out beforehand and use the highest temperature setting. metal lids can also be washed with the jars. This method sterilises using heat and the chemicals used in the dishwasher will do the job. Pop the jars in the oven to dry and warm up before adding the product
This is fine if you have plenty of jars to do, but a pain if it’s a small batch of jam from the last of the fruit.
2. Microwave – Wash the jars thoroughly and rise in fresh water leaving the jars wet. Place the wet jars in the microwave and run at full power for 45 seconds to a minute. The jars should be bone dry and hot when ready.
This is only suitable for plain glass jars with no metal fittings so clip lid Kilner jars are out. Call me old fashioned but I have never been too sure on how reliable this is. Lids still need to be boiled so its double the work.
3. Traditional oven method – wash the jars until spotless, rinse in fresh water then place the jars on a tray and put into the oven pre heated to 160˚c for about 10+ minutes when they should be completely dry and very hot (see tips below).
This is my recommended method, its reliable and not too much trouble. Works for plain glass and Kilner type jars. Beware the jars are very hot make sure you can handle them safely.
4. Immersing the jars, and lids in near boiling water 90˚+ for at least 10 minutes.
This works well and is reliable, handy to be able to do the lids at the same time. The main drawback is the danger of handling jars full of boiling water. Also, you may not have a pan large enough to hold all the jars you need.
Safety and filling tips.
I would always recommend clean rubber gloves when working with hot jams and chutneys. They will protect your skin and keep bacterial from your skin entering the food. Remember the jars will be hot have good oven gloves or tongs to grab the jars. Use silicone tipped tongs that will grip the glass don’t use plain metal as they may slip and cause an accident. Never place the hot jars onto a cold surface as the glass may crack and render the jar useless. I prefer to use a heatproof silicone mat to fill the jars on. Always fill hot jars with a hot filling. Never fill a hot jar with a cold filling or vice versa.
Always use a jam funnel to fill the jars and remember to ensure the funnel and any spoons or ladles are sterile. If using clip top Kilner jars the rubber seals should be placed in simmering water for 3 minutes before use. Metal lids can be processed in boiling water or through the oven.
Always label your jars not just with the contents but when it was made. I bet if you dive deep into the back of your kitchen cupboards a few food antiques will come to light.
Don’t be put off preserving by all of this, its quite straightforward once you understand the principles. Making your own preserves is relatively easy and you can benefit from your labors right through the dark winter months.
Additional reading.
Do look up the government website to get further information on food safety
enjoy life !
John.